The best mods for the Wife's Foreman 500 was the jet kit ( $75 ).. Great throttle response and snap..and the HMF QS1 Pipe ( $210 to the door ).. These will overcome any tire size ( within reason ) that you run. Go with these and watch your bike COME TO LIFE. If you notice, most of the bikes ( not all ) have these and there is a reason for that. Good luck and ride safe. Hope this helps.